Mine roof support assembly

ABSTRACT

A mine roof support assembly comprises three basically similar mine roof support units positioned in a side-by-side relationship along a beam. The central unit is fastened to the beam for movement therewith, and the two outer units are flexibly connected to the beam by respective guide rod assemblies. Each of the outer units is provided with an alignment device, such as a short working stroke hydraulic ram, which acts on the beam in the direction of the longitudinal axis of the beam.

BACKGROUND TO THE INVENTION

This invention relates to a mine roof support assembly constituted bythree mine roof support units positioned side-by-side along a beam.

A known form of assembly of this type has the central unit fastened tothe beam for movement therewith and the two outer units connected to thebeam by means of respective guide rod assemblies. Where the floor of themine working is uneven, or where there is a relatively steep incline ordip in the floor level, problems arise in ensuring satisfactoryalignment of the units and the beam. This is particularly troublesomewhen the assembly is used as a support for a longwall face.

DT-OS 2,337,218 described a mine roof support assembly of this type inwhich the central unit forms an abutment for the advance of the twoouter units. The guide rod assemblies of the outer units are constitutedby resilient guide rods connected to the beam, and the advance rams ofthe outer units are also connected to the beam. In order to align thisassembly, an aligning ram is positioned between the central unit and theouter unit which lies below it down the incline, the purpose of thisalignment ram being to align the central unit relative to the beam andthus also relative to the two outer units. However, it is not alwayspossible with this assembly to align the beam itself.

DT-OS 1,583,091 describes an assembly having three mine roof supportunits, the two outer units being connected by alignment rams which arepositioned between these two units in the manner of guide bars. Aseparate alignment device, associated with these rams, is provided foraligning the central unit. This type of arrangement is not suitable,however, for the type of assembly having a beam fastened to the centralunit.

DT-OS 2,453,225 describes a longwall face mine roof support assemblyconstituted by three units. Here, the central unit carries a generallyU-shaped guide bar, the two parallel arms of which form guide rods forthe two outer units. The U-shaped guide bar is longitudinally adjustableby means of an alignment ram so that the spacing of the units can bevaried. Again this type of arrangement is not suitable for the type ofmine roof support assembly which has a beam fastened to its centralunit.

It is the main object of the invention to construct a mine roof supportassembly of the type defined above which permits all the units and thebeam to be aligned even where the floor level of the mine working dipsappreciably and without the adaptability of the individual units to anyuneveness of the floor being affected.

SUMMARY OF THE INVENTION

The present invention provides a mine roof assembly comprising threemine roof support units positioned side-by-side along a beam, thecentral unit being fastened to the beam for movement therewith, and eachof the two outer units being connected to the beam by means of arespective guide rod assembly, wherein each of the outer units isprovided with an alignment device which acts on the beam, whereby thebeam is displaceable in the direction of its longitudinal axis.

Preferably, each of the alignment devices acts between the correspondingouter unit and the guide rod which connects that unit to the beam. Withthis form of assembly, it is possible to displace the beam in thedirection of its longitudinal axis, that is to say in the longitudinaldirection of a longwall face. Thus, by using the alignment devicesassociated with the two outer units, it is possible to adjust theposition of the beam to account for the effect of any incline in thefloor level of the mine working. Since the central unit is fastened tothe beam for movement therewith, this unit is automatically alignedtogether with the beam. The outer units can then be aligned relative tothe beam by means of their guide rod assemblies. Consequently, alignmentrams, which are interposed in the manner of guide rods between adjacentpairs of units, are not required.

Advantageously, each alignment device comprises an alignment ram whosepiston rod carries a coupling member which transmits force to the beamvia the associated guide rod assembly. Each coupling member may beprovided with an aperture through which the corresponding guide rodassembly passes with a vertical clearance. Preferably, each alignmentram is mounted so that its working stroke lies in a direction parallelto the longitudinal axis of the beam. This means that alignment ramshaving only a short working stroke can be utilised.

Each coupling member may be fixed to a respective push rod which isconnected to the corresponding piston rod by means of a bridge member,each push rod being parallel to the associated piston rod. Thus, eachalignment ram forms a compact unit together with its push rod andcoupling member, and so can be interposed between the front end of itsguide rod assembly and the beam.

Preferably, the guide rod assembly of each outer unit is constituted bya respective resilient guide rod whose front end is connected to thebeam and whose rear end is slidably supported on guide means provided onthe corresponding unit, and each guide rod is pivotally connected at itsfront end to the beam. Advantageously, the rear end of each guide rod isprovided with a transverse yoke which slides on said guide means.

Each of the outer units may be provided with an advance ram whoseworking stroke lies in a direction substantially perpendicular to thelongitudinal axis of the beam. In this case, each advance ram may bepivotally connected to the corresponding transverse yoke.

Each support unit may have a floor sill, and each alignment device maybe mounted on upstanding parallel brackets projecting upwards from thefront end of the corresponding floor sill. Preferably, each of the floorsills is constituted by two parallel, spaced apart sections. In thiscase, said upstanding brackets project upwards one from each section ofeach floor sill, and the guide rod assembly of each outer unit ismounted in the space between the two sections of the floor sill of thatunit. It is also convenient for the advance ram of each outer unit to bemounted above the guide rod assembly of that unit.

Preferably, the central unit is connected to the beam by means of a pairof resilient guide rods, and the resilient guide rods of the centralunit are mounted in the space between the two sections of the floor sillof that unit.

Usually, the beam is connected to, or forms part of, the longwallconveyor provided adjacent to the longwall face for removing wonmaterial. Thus, this type of assembly can also be used for aligning andanchoring a longwall conveyor.

The invention also provides a method of aligning a mine roof supportassembly which comprises three mine roof support units positionedside-by-side along a beam, the central unit being fastened to the beamfor movement therewith and each of the two outer units being connectedto the beam by means of a respective guide rod assembly, the methodcomprising the steps of aligning the beam and the central unit by meansof alignment devices associated with the two outer units, with the twoouter units anchored, and aligning the two outer units by means of theirguide rod assemblies with the central unit anchored.

BRIEF DESCRIPTION OF THE DRAWINGS

A mine roof support assembly constructed in accordance with theinvention will now be described, by way of example, with reference tothe accompanying drawings, in which:

FIG. 1 is a plan view of three adjacent units of the mine roof supportassembly;

FIG. 2 is a part-sectional side elevation through one of the units ofFIG. 1; and

FIG. 3 is an end elevation of the unit of FIG. 3.

DESCRIPTION OF PREFERRED EMBODIMENT

Referring to the drawings, FIG. 1 shows a mine roof support assemblycomprising three basically similar units I, II and III arranged in aside-by-side, parallel relationship. Each unit I, II and III has a floorsill structure 10 which supports two hydraulic telescopic props 14connected thereto by ball-and-socket joints 13. The floor sill structure10 of each unit I, II and III is effectively sub-divided in thelongitudinal direction, that is to say in the direction S of advance,and composed of separate sill sections 11 and 12. The heads of the props14 support a roof cap (not shown) either directly, or indirectly bysupporting a goaf shield (not shown) hinged thereto.

The central unit II is connected to a beam 15 by means of two resilientguide rods 16 which are located in the space 17 between the two floorsill sections 11 and 12, the rear (goaf side) ends of the rods beingfixed to a transverse yoke 18 which is mounted on guides 19 fixed to theinner lateral faces of the sections 11 and 12. The front (working faceside) ends of the rods 16 are fixed to a block 20 which in turn is fixedto the beam 15. The central unit II is then connected to the beam 15 insuch a manner that, apart from slight movements for taking up anyuneveness in the floor of the mine working the two parts act as oneduring advance of the assembly.

Each of the outer units I and III is connected to the beam 15 by meansof a respective guide rod assembly 22 and vertical pivot joint 21. Eachguide rod assembly 22 is constituted by a single resilient guide rodlocated in the space 17 between the two floor sill sections 11 and 12 ofthe unit I or III in question. The rear (goaf side) end of each guiderod 22 is fixed to a transverse yoke 23 which is slidably mounted onguides 19 fixed to the inner lateral faces of the corresponding floorsill sections 11 and 12. The cylinder 25 of a respective hydraulicadvance ram is pivotally connected (about a horizontal pivot 26) to apair of brackets 24 attached to each of the transverse yokes 23. Therams 25 are positioned above the corresponding guide rods 22 and theirpiston rods 28 are pivotally connected (about corresponding horizontalpivots 29) to pairs of parallel brackets 27 attached to the floor sillsections 11 and 12 at the front (working face) ends of the units I andIII.

The brackets 27 also support short-stroke hydraulic alignment rams 30whose axes lie parallel to the longitudinal axis of the beam 15. Eachram 30 is mounted to its support brackets 27 in such a manner that itscylinder cannot move relative thereto in the direction of thelongitudinal axis of the beam, whereas the floor sill sections 11 and 12are vertically movable, to a limited extent, relative to the cylinder.The piston rod 31 of each ram 30 is rigidly connected, via a bridgemember 32, to a respective push rod 33 which is arranged parallel to,and beneath the corresponding ram 30. Each push rod 33 is guided inguide apertures (not shown) in the corresponding brackets 27. An ovallink 34 is fastened to the underside of each push rod 33, thecorresponding guide rod 22 passing through each link with a limitedvertical freedom of movement.

In use, if the alignment rams 30 of the outer units I and III arepressurised, the push rods 33 will be displaced by the extending (orretracting) piston rods 31 in the direction of the arrow R. As the links34 are fixed to their push rods 33, they also move in the direction ofthe arrow R. Thus, if the props 14 of the central unit II are notpressurised, the beam 15 together with the central unit II will also bedisplaced in the direction R, that is to say in the longitudinaldirection of the longwall working face. The force from the alignmentrams 30 is, thus, transmitted via the links 34 and the resilient guiderods 22 to the beam 15. Because of their resilience, the guide rods 22may also be elastically deformed, in the direction of the applied force,during this alignment process. After the beam 15 has been aligned inthis manner, and after the central unit II has been re-anchored bysubjecting its props 14 to pressure, the two outer units I and III arealigned with respect to the beam 15, once their props 14 aredepressurised, by means of their guide rod assemblies 22.

The advance of the roof support assembly in the direction S is effectedin the usual way by means of the advance rams 25, the central unit IIbeing advanced first (together with the beam 15), and the two outerunits I and III then being advanced in a follow-up sequence. During theadvance of the central unit II its props 14 are depressurised and thetwo outer units I and III form abutments for the advance, and during theadvance of the outer units their props 14 are depressurised and thecentral unit acts as an abutment.

The three units I, II and III may be supported against one another inthe goaf side area. This can be effected by means of laterallyextensible side bars known per se which are arranged on the goafshields.

In view of the fact that the guide rod assemblies of the two outer unitsI and III each comprise only a single guide rod 22 which is located inthe relatively large space 17 between the corresponding floor sillsections 11 and 12, it is possible to displace the beam 15 from itsrepresented central position by approximately 50 to 100 millimeters ineither direction R.

We claim:
 1. A mine roof support assembly comprising three mine roofsupport units positioned side-by-side along a beam, the central unitbeing fastened to the beam at an invariant distance therefrom formovement therewith, each of the two outer units being connected to thebeam adjacent to a respective end thereof by means of a respective guiderod assembly, each of the outer units being provided with an alignmentdevice which acts on the beam, whereby the beam is displaceable in thedirection of its longitudinal axis, each alignment device comprising analignment ram whose piston rod carries a coupling member which transmitsforce to the beam via the associated guide rod assembly, and whereineach coupling member is fixed to a respective push rod which isconnected to the corresponding piston rod by means of a bridge member,each push rod being parallel to the associated piston rod.
 2. A mineroof support assembly comprising three mine roof support unitspositioned side-by-side along a beam, the central unit being fastened tothe beam at an invariant distance therefrom for movement therewith, eachof the two outer units being connected to the beam adjacent to arespective end thereof by means of a respective guide rod assembly, eachof the outer units being provided with an alignment device which acts onthe beam, whereby the beam is displaceable in the direction of itslongitudinal axis, and wherein the guide rod assembly of each outer unitis constituted by a respective resilient guide rod whose front end isconnected to the beam and whose rear end is slidably supported on guidemeans provided on the corresponding unit.
 3. An assembly according toclaim 2, wherein each guide rod is pivotally connected at its front endto the beam.
 4. An assembly according to claim 2, wherein the rear endof each guide rod is provided with a transverse yoke which slides onsaid guide means.
 5. An assembly according to claim 4, wherein each ofthe outer units is provided with an advance ram whose working strokelies in a direction substantially perpendicular to the longitudinal axisof the beam.
 6. An assembly as claimed in claim 5, wherein each advanceram is pivotally connected to the corresponding transverse yoke.
 7. Amine roof support assembly comprising three basically similar mine roofsupport units positioned side-by-side along a beam, the central unitbeing fixed to the beam in a substantially rigid manner for movementtherewith in a substantially fixed position relative thereto, and eachof the two outer units being flexibly connected to the beam by means ofa respective resilient guide rod, each of the outer units being providedwith an alignment device which acts between that unit and the guide rodwhich connects that unit to the beam, whereby the beam is displaceablein the direction of its longitudinal axis, wherein each alignment deviceis constituted by a short working stroke alignment ram mounted so thatits working stroke lies in a direction parallel to said longitudinalaxies of the beam, the piston rod of each said alignment ram carrying acoupling member which transmits force to the beam via the associatedguide rod, the coupling members each being provided with an elongateaperture through which the corresponding guide rod passes with avertical clearance.
 8. A mine roof support assembly comprising:threemine roof support units horizontally positioned side-by-side along abeam extending along a mineral long face in a mine; means fixing thecentral roof support unit to said beam for movement therewith in boththe direction of the longitudinal axis of said beam and also in thedirection toward the face; individual guide rod means extending in adirection perpendicular to the longitudinal axis of said beam andpivotally connecting each of the units to a respective end of said beamfor permitting longitudinal movement of said beam relative to said outerunits; individual ram means, mounted on each outer unit and coupled tosaid beam, for displacing said beam and central unit relative to saidouter units in the longitudinal direction of said beam, the stroke ofsaid ram means being in a direction parallel to the longitudinal axis ofsaid beam; and means for anchoring the outer ends during thelongitudinal displacement of the said beam.
 9. An assembly according toclaim 8 further comprising individual coupling means coupling saidindividual guide rod means to the piston rods of the correspondingindividual ram means so that movement of the piston rod is transmittedthrough said guide rod means to said beam.
 10. An assembly according toclaim 9 wherein each coupler means is provided with an aperture throughwhich the corresponding guide rod means passes with a verticalclearance.
 11. An assembly according to claim 9 wherein each supportunit has a floor sill formed by two parallel, spaced apart sillsections, wherein each ram means is mounted on upstanding parallelbrackets projecting upwards from the front end of the correspondingfloor sill, wherein the guide rod means of each outer unit is mounted inthe space between the two sill sections of that unit, and wherein saidfixing means for the central unit comprises a pair of resilient guiderods mounted in the space between the sill sections of that unit.
 12. Anassembly according to claim 9 further comprising an advance ram on eachof said outer units and having a working stroke in a directionsubstantially perpendicular to the longitudinal axis of said beam.